Rare presentation of necrotising otitis externa: isolated abducens nerve palsy

An immunocompetent, non-diabetic man in his 90s presented to A&E with headache and sudden-onset left abducens nerve palsy. He was treated for recurrent left otitis externa six months previously, with a normal CT of the petrous bone at the time.Ear appearances were unremarkable, but CT petrous bones revealed extensive skull base osteomyelitis extending to the petrous apex. MRI skull base and nuclear medicine technetium-99m hexamethylpropyleneamine-oxime white cell scanning confirmed active osteomyelitis.Necrotising otitis externa (NOE) is a complication of otitis externa and is more common in the elderly and immunosuppressed. Facial nerve palsies can occur due to anatomical proximity but there are only two other reported cases of isolated abducens nerve palsy associated with NOE. This case highlights the importance of fully treating otitis externa and the complexities of managing NOE in elderly and frail patients. It also illustrates the use of different imaging modalities to differentiate active and historic osteomyelitis.